diff --git a/src/main/agent-hooks/managed-hook-local-filesystem.test.ts b/src/main/agent-hooks/managed-hook-local-filesystem.test.ts
index 91a1ca62eb6..f6dcf14471a 100644
--- a/src/main/agent-hooks/managed-hook-local-filesystem.test.ts
+++ b/src/main/agent-hooks/managed-hook-local-filesystem.test.ts
@@ -6,9 +6,11 @@ import { installRemoteManagedAgentHooks } from './remote-managed-hook-installers
 import { createManagedHookLocalFilesystem } from './managed-hook-local-filesystem'
 
 const tempHomes: string[] = []
+const tempRoot = process.platform === 'win32' ? tmpdir() : '/tmp'
 
 async function createTempHome(): Promise<string> {
-  const home = await mkdtemp(join(tmpdir(), 'orca-managed-hooks-'))
+  // Why: mkdir-p probes ancestors; macOS's per-user temp directory can contain hundreds of thousands of entries.
+  const home = await mkdtemp(join(tempRoot, 'orca-managed-hooks-'))
   tempHomes.push(home)
   return home
 }
diff --git a/src/main/agent-hooks/wsl-hook-relay-live.integration.test.ts b/src/main/agent-hooks/wsl-hook-relay-live.integration.test.ts
index a7c25f02cc2..ab6d6a03e45 100644
--- a/src/main/agent-hooks/wsl-hook-relay-live.integration.test.ts
+++ b/src/main/agent-hooks/wsl-hook-relay-live.integration.test.ts
@@ -7,7 +7,6 @@
 // exercises minus the wsl.exe byte transport (validated separately on-rig).
 import { execFileSync, spawn, type ChildProcessWithoutNullStreams } from 'node:child_process'
 import { existsSync, mkdtempSync, readFileSync, rmSync } from 'node:fs'
-import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import { createServer } from 'node:net'
 import { afterEach, beforeAll, describe, expect, it, vi } from 'vitest'
@@ -59,7 +58,7 @@ describe.skipIf(process.platform === 'win32')(
     })
 
     it('delivers a Claude hook POST from the live relay into ingestRemote and installs guest hooks', async () => {
-      fakeHome = mkdtempSync(join(tmpdir(), 'wsl-live-home-'))
+      fakeHome = mkdtempSync(join('/tmp', 'wsl-live-home-'))
       const preferredPort = await pickFreePort()
       const version = readFileSync(join(BUNDLE_DIR, '.version'), 'utf8').trim()
 
diff --git a/src/main/agent-hooks/wsl-hook-relay-manager.test.ts b/src/main/agent-hooks/wsl-hook-relay-manager.test.ts
index 60bb3cbb2f9..39a9736a526 100644
--- a/src/main/agent-hooks/wsl-hook-relay-manager.test.ts
+++ b/src/main/agent-hooks/wsl-hook-relay-manager.test.ts
@@ -3,7 +3,6 @@
 // the per-distro relay manager state machine with fault injection.
 import { EventEmitter } from 'node:events'
 import { existsSync, mkdtempSync, readFileSync, rmSync } from 'node:fs'
-import { tmpdir } from 'node:os'
 import { join } from 'node:path'
 import type { ChildProcessWithoutNullStreams } from 'node:child_process'
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
@@ -34,9 +33,13 @@ function createGuestHarness(): GuestHarness {
   const clientDataCallbacks: ((data: Buffer) => void)[] = []
   const closeCallbacks: (() => void)[] = []
   const transport: MultiplexerTransport = {
-    write: (data) => {
-      setImmediate(() => relayFeed?.(data))
+    write: (data, onSettled) => {
+      setImmediate(() => {
+        relayFeed?.(data)
+        onSettled?.({ ok: true })
+      })
     },
+    supportsWriteSettlement: true,
     onData: (cb) => {
       clientDataCallbacks.push(cb)
     },
@@ -44,21 +47,24 @@ function createGuestHarness(): GuestHarness {
       closeCallbacks.push(cb)
     }
   }
-  const guestDispatcher = new RelayDispatcher((data: Buffer) => {
-    setImmediate(() => {
-      for (const cb of clientDataCallbacks) {
-        cb(data)
-      }
-    })
-  })
+  const guestDispatcher = new RelayDispatcher(
+    (data: Buffer, onSettled) => {
+      setImmediate(() => {
+        for (const cb of clientDataCallbacks) {
+          cb(data)
+        }
+        onSettled({ ok: true })
+      })
+    },
+    { supportsWriteCallback: true }
+  )
   relayFeed = (data) => guestDispatcher.feed(data)
   const mux = new SshChannelMultiplexer(transport)
   return { transport, guestDispatcher, mux }
 }
 
-// Why skipIf: the fs bridge runs inside the Linux guest and is POSIX-only by
-// design (posix.resolve). On a Windows dev host tmpdir() yields C:\ paths the
-// bridge correctly refuses; Windows coverage comes from the live rig runs.
+// Why skipIf: the fs bridge runs inside the Linux guest and is POSIX-only;
+// Windows coverage comes from the live rig runs.
 describe.skipIf(process.platform === 'win32')(
   'createWslHookSftpAdapter over the guest fs bridge',
   () => {
@@ -66,7 +72,7 @@ describe.skipIf(process.platform === 'win32')(
     let harness: GuestHarness
 
     beforeEach(() => {
-      home = mkdtempSync(join(tmpdir(), 'wsl-guest-home-'))
+      home = mkdtempSync(join('/tmp', 'wsl-guest-home-'))
       harness = createGuestHarness()
       registerWslHookFsHandlers(harness.guestDispatcher, home)
     })
diff --git a/src/main/ssh/ssh-relay-session-managed-hooks.test.ts b/src/main/ssh/ssh-relay-session-managed-hooks.test.ts
index f225b113436..95492aa3a3a 100644
--- a/src/main/ssh/ssh-relay-session-managed-hooks.test.ts
+++ b/src/main/ssh/ssh-relay-session-managed-hooks.test.ts
@@ -7,15 +7,24 @@ import { SshRelaySession } from './ssh-relay-session'
 import type { SshConnection } from './ssh-connection'
 import { createMockDeps, mockDeploySuccess } from './ssh-relay-session-test-fixtures'
 
-const { muxRequestMock } = vi.hoisted(() => ({ muxRequestMock: vi.fn() }))
+const { muxRequestMock, openConsumerSessionMock } = vi.hoisted(() => ({
+  muxRequestMock: vi.fn(),
+  openConsumerSessionMock: vi.fn()
+}))
 
 vi.mock('./ssh-relay-deploy', () => ({ deployAndLaunchRelay: vi.fn() }))
 vi.mock('./ssh-relay-deploy-helpers', () => ({ execCommand: vi.fn().mockResolvedValue('') }))
+vi.mock('./ssh-pty-consumer-session', () => ({
+  SSH_PTY_SOURCE_WINDOW_SU: 256 * 1024,
+  openSshPtyConsumerSession: openConsumerSessionMock
+}))
 vi.mock('./ssh-channel-multiplexer', () => ({
   SshChannelMultiplexer: class MockSshChannelMultiplexer {
     notify = vi.fn()
+    notifyWithSettlement = vi.fn()
     request = muxRequestMock
     onNotification = vi.fn().mockReturnValue(() => {})
+    onNotificationByMethod = vi.fn().mockReturnValue(() => {})
     onRequest = vi.fn().mockReturnValue(() => {})
     onDispose = vi.fn().mockReturnValue(() => {})
     dispose = vi.fn()
@@ -68,6 +77,11 @@ describe('SshRelaySession managed hooks', () => {
   beforeEach(() => {
     vi.clearAllMocks()
     process.env.ORCA_FEATURE_REMOTE_AGENT_HOOKS = '1'
+    openConsumerSessionMock.mockImplementation(async (_mux, options) => ({
+      mode: 'legacy-fallback',
+      clientInstanceId: options.clientInstanceId,
+      serverBuildId: 'test-relay-build'
+    }))
     mockDeploySuccess()
   })